1. Field of the Invention
This invention relates generally to pressure-tight closures. More particularly, it relates to a structure for securing two parts of a valve together in a leakproof relationship.
2. Description of the Prior Art
In assembly of high pressure fluid handling equipment, it is necessary to secure parts of a valve together in such a way as to prevent leaks of the contained fluid. It is frequently desirable that the two parts be secured together so as to be conveniently and quickly separable in the event that maintenance is required. One such situation is encountered in securing a valve bonnet to a valve body.
Heretofore, it has been common to provide a valve body and a flanged valve bonnet each having a flat surface, and a gasket fitting between these flat surfaces. To effect a seal between these surfaces, bolts or studs have been used which are inserted through holes near the periphery of the valve bonnet flange and screw into holes tapped into the valve body. With this arrangement it is necessary to provide sufficient space around the bolt heads or nuts so that a wrench may be used to remove them when maintenance is required. Moreover, at least four, and frequently six or eight, bolts are normally employed in a closure of this sort, and it is necessary to remove all of these bolts to gain access to the interior of the valve.